Sunlight is the one growing condition you cannot really substitute. Water, soil and feeding can all be adjusted; light mostly decides what is possible in a given spot.
What the labels mean
- Full sun: six or more hours of direct sunlight a day.
- Part sun or part shade: roughly four to six hours, often with shade in the afternoon.
- Full shade: under four hours of direct light, or dappled light through the day.
Measure before you plant
Pick a clear day and check your intended spot every two hours from morning to evening, writing down whether it is in direct sun or shade. Total the sunny hours at the end of the day.
Do this in the season you plan to grow. A bed that is bright in early spring can be deeply shaded once nearby trees leaf out.
Matching plants to light
- Six hours or more: tomatoes, peppers, cucumbers, zucchini, beans, sunflowers, zinnias, lavender, rosemary.
- Four to six hours: lettuce, spinach, radishes, chard, parsley, mint, cilantro.
- Under four hours: leafy greens only, and expect slower, smaller growth.
Working with less light than you would like
Grow in containers you can move through the day, use pale walls and fences to bounce light back into the bed, and lean toward leaf crops rather than fruiting ones.
Thinning overhanging branches can also transform a bed, and often costs nothing but an afternoon.
When too much sun is the problem
In hot climates, afternoon shade is a benefit rather than a limitation. Lettuce, cilantro and other cool-season crops last far longer with some protection from the harshest part of the day.
Practical tips to take with you
Check more than once
Track the same spot in spring and summer because trees, fences, and the sun's path change the light through the year.
Use the brightest space wisely
Reserve your sunniest area for fruiting crops and place leafy vegetables where afternoon shade offers protection.
Watch reflected heat
A sunny wall can intensify warmth and dryness. It may help peppers and rosemary but stress lettuce and cilantro.
This article offers general gardening guidance. Growing conditions differ by climate, soil and season, so treat it as a starting point for your own garden.